JPS6339397Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a valve control device for a carburetor of an automobile engine or the like.

As is well known, when starting an automobile engine, etc., the intake valve of the carburetor is closed to make the air-fuel ratio of the mixture supplied from the carburetor richer than during normal operation. . However, there are some models that control the opening of the chiyoke valve using negative intake pressure (for example, Japanese Patent Publication No. 45-37495
According to the above publication, when the outside air pressure decreases, such as when the automobile is used at a high altitude, the intake negative pressure also decreases. As a result, the opening degree of the choke valve becomes smaller than on a flat ground, and the amount of fuel supplied relative to the amount of intake air increases, creating a tendency for overbalance, which leads to undesirable phenomena such as an increase in the proportion of hydrocarbons and carbon monoxide in the exhaust gas. wake up Therefore, a control device has been devised that can highly correct the opening degree of the valve of the carburetor, but there are few devices that can satisfactorily achieve such a purpose.

For example, Japanese Utility Model Application Publication No. 53-133030 describes an example of a device for controlling the opening degree of a choke valve according to fluctuations in outside air pressure, but this device does not necessarily control the engine. It cannot be started properly. In other words, the device described in Japanese Utility Model Application Publication No. 53-133030 is merely a device that slightly increases the opening of the chiyoke valve when the outside air pressure becomes low when the engine is stopped or cranked. It is not intended to correct the altitude of the chiyoke valve opening after a complete explosion. Therefore, in such devices, the engine actually starts (complete explosion).
However, when negative intake pressure occurs, the opening degree of the choke valve remains the same as during cranking, resulting in an excessively rich air-fuel ratio.

The device itself that opens the choke valve in response to the negative intake pressure generated after a complete explosion is known in the technical field;
The publication describes a system in which intake negative pressure is introduced into one of the divided actuator chambers through a diaphragm connected to the check valve, and the diaphragm operates to open the check valve in accordance with the magnitude of the negative pressure. An example of a type of device is shown. however,
This device is not provided with any mechanism for controlling the opening degree of the choke valve in response to fluctuations in outside air pressure. Therefore, even if such a device is used, the outside air pressure will be low at high altitudes, etc.
Correspondingly, when the intake negative pressure decreases, the opening degree of the choke valve decreases, resulting in overburden.

In view of the above circumstances, the purpose of the present invention is to control the opening degree of the choke valve at the time of complete explosion, including when the outside air pressure fluctuates, thereby providing an engine that emits fewer harmful substances. An object of the present invention is to provide a valve control device for a carburetor.

A device for achieving the above object of the present invention includes an air-fuel ratio correction device that corrects the fuel supplied to the intake passage by supplying correction air to the fuel passage of the carburetor in response to a decrease in outside air pressure; The valve includes an actuator that is partitioned into a first chamber and a second chamber by a diaphragm connected to the choke valve, and supplies negative intake pressure downstream of the throttle valve to the first chamber. The diaphragm is displaced toward the first chamber by the negative pressure, thereby opening the check valve.

and a yoke valve opening correction means that adjusts the operation of the actuator according to a decrease in outside air pressure to maintain the yoke valve opening at a constant opening that is substantially the same as the yoke valve opening in a lowland area regardless of changes in outside air pressure. It is characterized by having the following.

By using the Chiyork valve control device of the present invention having the above-mentioned configuration, the opening degree of the Chiyork valve after a complete explosion of the engine can be changed from the closed state during cranking due to the difference in the pressure receiving areas of the diaphragms on both chamber sides of the actuator. The opening degree is appropriately adjusted to the degree required at the time of a complete engine explosion, and even if the outside air pressure fluctuates, the intake negative pressure that is corrected according to the fluctuation is introduced into the second chamber, thereby increasing the pressure of the chioke valve. Even at high altitudes with low temperatures, the valve opening can be maintained at approximately the same degree as at low altitudes.

In order to further clarify the structural features and effects of the present invention, the present invention will be described below with reference to the accompanying drawings.

The accompanying drawings illustrate a typical carburetor that includes one embodiment of the Chiyork valve control system of the present invention.

In the figure, the area surrounded by the dashed line indicates the carburetor body, reference number 1 is the float chamber, reference number 2 is the float chamber,
3 indicates a throttle valve, 3 a main nozzle, 4 a bench lily, and 5 a choke valve, respectively. Further, 6 is a main air bleed, 7 is a first slow air bleed, and 8 is a second slow air bleed. Furthermore, 9 is an idle port, 10 is a slow port, 11 is an air passage, 11a is an orifice,
12 is an idle adjust screw, 13 is a main jet, and 14 is a slow jet. The operation of a vaporizer comprising these elements is well known in the art and will not be discussed here. Further, the carburetor shown in the figures is provided as an example for explaining the present invention, and it goes without saying that the present invention is not intended to be applied only to the illustrated carburetor.

Reference numeral 16 denotes an actuator of the chiyoke valve control device of the present invention, and this actuator is connected to the first chamber 18 and the second chamber by a diaphragm 17 as shown in the figure.
It is divided into chamber 19. diaphragm 17
is fixed to one end of the rod 20, and the rod 20
The other end is fixed to the outer end of the bimetal 21. The inner end of the bimetal 21 is fixed to the choke valve 5. In this way, the diaphragm 17
is connected to the check valve 5, and thus the displacement of the diaphragm 17 is transmitted to the check valve 5 via the bimetal 21 to open and close the valve. In the illustrated example, the diaphragm is connected to the chiyok valve via a bimetal so that the opening degree of the chiyok valve can be adjusted even in response to engine temperature changes, but the diaphragm is connected to the chiyoke valve via a bimetal. It may also be directly connected to the choke valve. Furthermore, the connection structure between the choke valve 5 and the rod 20 is as follows:
For example, there is a known structure in which the rod 20 is connected to a lever that is integrated with a support shaft that rotatably supports the inner end of the bimetal, and the outer end of the bimetal is connected to a lever that is integrated with the rotating shaft of the York valve. However, the present invention is not limited to the above embodiments.

The first chamber 18 and the second chamber 19 of the actuator 16 have intake negative pressure inlets 22 and 23, respectively. As mentioned above, one of the characteristics of the valve control device of the present invention is that the pressure receiving area on the second chamber side of the diaphragm in the actuator is made smaller than that on the first chamber side.
For this reason, in the embodiment shown in the figure, one end of the bellows 36, the interior of which is open to the atmosphere, is fixed to the surface of the diaphragm on the second chamber side, thereby increasing the pressure receiving area of the diaphragm 17 on the second chamber 19 side. is configured to be smaller than the pressure receiving area of the diaphragm 17 on the first chamber 18 side. Note that it is also possible to make the pressure receiving area of the diaphragm on the second chamber side smaller than the pressure receiving area on the first chamber side by using means other than the bellows.

A spring 24 is disposed on the first chamber side of the illustrated diaphragm, and when the diaphragm is inactive, this spring presses the diaphragm to the left in the figure to close the Chikaak valve. Further, the rod-shaped member 25, which is interlocked with the diaphragm 17 via the plate-shaped member 26, changes the maximum displacement of the diaphragm and, therefore, the maximum opening degree of the valve by coming into contact with the rear end wall of the actuator 16. This is a stipulating stopper.

On the other hand, on the second chamber side, the frame member 35 functions as a stopper that determines the position of the diaphragm when it is inactive.

Reference numeral 27 in the figure indicates an altitude correction device that operates to supply air to the second chamber of the actuator in response to fluctuations in outside air pressure in the Chiyoke valve control device of the present invention. This correction device includes the atmosphere opening chamber 27a
A bellows 28 is provided inside, and the bellows lowers the valve 30 connected to the bellows to close the outside air inlet 29 under normal (low altitude) outside air pressure, but when the outside air pressure is low at high altitudes, When it expands, the valve 30 is raised and the inlet 29 is opened.
is opened to introduce outside air into the correction air passage 31. It should be noted that the altitude correction device 27 is connected to the main correction passage 32 as shown in the figure, and adjusts the main nozzle 3 according to fluctuations in outside air pressure, if necessary.
It may also be used in common to adjust the amount of air bleed on the side.

The correction air passage 31 has one end communicating with the introduction port 29 and the other end communicating with the air passage 11 downstream of the orifice 11a, and a passage 34 branched from the correction air passage 31 is an introduction port of the second chamber 19 of the actuator 16. It is connected to 23. The intake negative pressure introduction passage 33 is connected to the introduction port 22 of the first chamber 18 . In addition, in the embodiment shown in the figure, the high-speed correction passage 31 is connected to the idle port 9 via the air passage 11, so that altitude correction of the fuel flow rate from the idle port 9 during idling is also possible. I'm getting better at it, but
The passage 31 is not connected to such a port, but is connected to a negative pressure outlet separately provided in the intake passage on the downstream side of the throttle valve 2, so that the control of the choke valve, which is the object of the present invention, is performed by connecting the fuel to the idle port 9. It can also be done completely independently of control.

The chiyoke valve control device configured as described above operates as follows when starting the engine. For example, if the engine is started on flat ground (low ground), the intake negative pressure is extremely small during cranking, so the diaphragm 17 of the actuator is located on the left side in the figure, keeping the valve 5 closed.
When the engine is in a complete explosion state and a large intake negative pressure is generated in the intake passage, the intake negative pressure passes through the passage 33 and passes through the inlet 22 to the first chamber 18 of the actuator.
will be introduced in At this time, since the valve 30 of the altitude correction device 27 is in a closed state on flat ground, air does not enter the correction air passage 31 from the outside air inlet 29. Therefore, an intake negative pressure of substantially the same magnitude as that in the first chamber is also introduced into the second chamber 19 of the actuator through the passages 31, 34 and the inlet 23. Therefore, since the pressure receiving area of the diaphragm 17 is larger on the first chamber side than on the second chamber side, the overall force applied to the diaphragm due to negative pressure is larger on the first chamber side, and as a result, , the diaphragm is displaced to the right in the figure against the spring force of the spring 24, and in response, the bimetal is pulled to the right and the yoke valve is opened to the required opening degree.

Even when starting an engine at high altitudes where outside air pressure is low, if the same amount of negative intake pressure is introduced into each chamber of the actuator due to complete explosion, the diaphragm will move toward the right in the diagram according to the same principle as described above. This causes the valve to open.
However, at high altitudes, the magnitude of the intake negative pressure itself becomes smaller, so the amount of displacement of the diaphragm, that is, the opening degree of the choke valve, becomes smaller than at flatlands. Therefore, in the device of the present invention,
When the outside air pressure decreases, the altitude correction device is activated and air is introduced through the passage 31, thereby correcting the magnitude of the negative pressure introduced into the second chamber. ing. That is, as the outside air pressure decreases, air is introduced from the outside air inlet 29 into the passage 31 according to the opening degree of the valve 30, thereby causing negative pressure to be introduced into the second chamber via the passages 34 and 23. By correcting this so that the pressure is weakened (so that the absolute value of the pressure is increased), the diaphragm 17 is moved rightward in the figure, and the opening degree of the choke valve is further increased. Therefore, this opening degree is approximately the same as the opening degree of the Chiyoke valve in lowlands.

Thus, according to the present invention, depending on the performance of the target engine, the correlation between each element of the device of the present invention and the opening degree of the choke valve, for example, the pressure receiving area of the diaphragm of the actuator and the air introduced from the correction passage. By determining the correlation between the amount of air and the degree of opening of the chiyoke valve, it is possible to adjust the degree of opening of the chiyoke valve after a complete explosion to a desired value, even when the outside air pressure fluctuates. Therefore, by using the choke valve control device of the present invention, it is possible to obtain an excellent engine that can prevent mixture overburden and reduce hydrocarbons and carbon monoxide in exhaust gas.

[Brief explanation of the drawing]

The attached drawing shows one of the valve control devices of the present invention.
1 is a side cross-sectional view of a vaporizer including an embodiment; FIG. 16... Actuator, 17... Diaphragm, 18... First chamber, 19... Second chamber, 27...
Altitude correction device, 31... Correction air passage, 33...
Intake negative pressure introduction passage.

Claims (1)

[Scope of utility model registration request] an air-fuel ratio correction device that corrects the fuel supplied to the intake passage by supplying correction air to the fuel passage of the carburetor in response to a decrease in outside air pressure; a chiyoke valve disposed in the intake passage; and a chiyoke valve connected to the chiyoke valve. the actuator is divided into a first chamber and a second chamber by a diaphragm, and the intake negative pressure downstream of the throttle valve is introduced into the first chamber, and the diaphragm is displaced toward the first chamber by the negative pressure. In the carburetor control device, the pressure receiving area of the diaphragm on the second chamber side of the actuator is configured to be smaller than that on the first chamber side, and the pressure receiving area of the diaphragm on the second chamber side of the actuator is configured to be smaller than that on the first chamber side. An intake negative pressure introduction passage is provided which communicates with the intake passage of the second chamber, and atmospheric pressure is introduced into the intake negative pressure introduction passage according to a decrease in outside air pressure to weaken the intake negative pressure introduced into the second chamber. 1. A chiyoke valve control device for a carburetor, characterized in that it is provided with a chiyoke valve opening correcting means for maintaining the opening at a constant opening that is substantially the same as the chiyoke valve opening at a low altitude.